dollars to doughnuts

I assure you (that something will happen, with so much confidence that I would bet money against something less valuable). I lost my umbrella. Dollars to donuts it rains tomorrow! Dollars to donuts that Kevin will be late tonight—he's never on time.

If you say that it is dollars to doughnuts that something will happen, you mean that you are certain it will happen. Note: `Doughnuts' is sometimes spelled `donuts' in this expression. It's dollars to doughnuts that the bank of the future will charge more for its services. Well, I'll bet you, Alex, almost dollars to donuts that I'll wake up at 3am, as I do every morning now.

Absolutely, certainly. This expression is most often preceded by the verb “to bet” and indeed comes from wagering. If someone is willing to bet dollars against doughnuts, he or she is absolutely sure of winning, the pastries being considered worthless compared to hard cash. The term began to be employed in the late 1800s. F. W. Bronson used it in Nice People Don’t Kill (1940), “You can bet a dollar to a doughnut.” Alliteration no doubt helped it to survive.

Stakes for a bet on a certain outcome. In the days when a dollar was worth more than it is now and a doughnut cost considerably less, someone who was reasonably sure that an event would happen might preface his comment with “Dollars to doughnuts . . .” as in “Dollars to doughnuts, it'll rain before nightfall.”